The present invention relates to a sensor device for an electric machine, which has a machine component provided with pole teeth, for the purpose of detecting a movement relative to the machine component. The sensor device is equipped with a U-shaped or E-shaped yoke and a sensor, which is arranged in/on the yoke for the purpose of detecting a magnetic variable.
Sensor devices of this type can be used for any desired electric machines, such as DC motors, AC motors and three-phase motors, for example. In this case, they can also be used both in rotary motors and in linear motors. Specifically, in order to come close to a specific rotary angle in the case of rotary motors or specific path lengths in the case of linear motors, it is necessary to measure the present rotary angle or the present path length. In this case, the measurement is intended to take place as precisely as possible in order that the corresponding rotary angle or the corresponding path length can be approached precisely and quickly by means of a suitable regulating device. Knowledge of the position is also necessary in the case of synchronous machines for the correct energization of the motor.
Generally, optical measurement systems are used for position determination for linear motors. Disadvantages of an optical measurement are, however, that this is expensive to implement and that the optical measurement is very easily impaired or made impossible by contamination in the linear motor or in its environment, with the result that failure of the regulating device often occurs.